If you happen to have a supermicro server (X10SLH-F) and install Linux in UEFI mode in our case CentOS 7 and you want to enter the BIOS you’ll be surprised that you cannot with the keys provided in the very same BIOS boot screen – F2, DEL. The F11 and F12 also does not work for menu selection and network boot!

Even if you manage to press the DEL key and you see on the screen “Entering BIOS setup…” – the server WON’T enter BIOS, but will continue with the UEFI BIOS boot drive!

So what to do? Ammm break temporary your system by removing (renaming or moving) the EFI directory in your efi boot partition, resetting your server and holding pressed DEL key (again) on all start up screens of the server. When the UEFI BIOS boot entry is not valid any more and there are no other boot devices (and probably because we pressed DEL key) we were able to enter in the BIOS without remote hands on the collocation side or any other intervention on the server.

[root@srv ~]# mv /boot/efi/EFI/ /boot/efi/EFI_org
[root@srv ~]# reboot

This is the path in CentOS 7 and our standard partition layout:

[root@srv ~]# df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/sda3         26G  4.5G    20G  19% /
devtmpfs         7.8G     0   7.8G   0% /dev
tmpfs            7.8G     0   7.8G   0% /dev/shm
tmpfs            7.8G  8.5M   7.8G   1% /run
tmpfs            7.8G     0   7.8G   0% /sys/fs/cgroup
/dev/sda2        976M   98M   812M  11% /boot
/dev/sda1        200M  9.8M   191M   5% /boot/efi
tmpfs            1.6G     0   1.6G   0% /run/user/0

DO NOT forget to remove all other (virtual) CD/DVD ROM Devices and temporary disable your network PXE Server (if you have any in the network)

Because it when the UEFI BIOS cannot find the EFI file saved in the UEFI BIOS BOOT drive it might follow the boot order before entering the BIOS!

Enter the bios by remote console on our X9 boards with UEFI bios

Apparently there is an issue with X8 and X9 supermicro boards in UEFI mode BIOS: https://www.supermicro.com/support/faqs/faq.cfm?faq=14029
So for someone it could be useful pressing and holding “ESC” + “-” or F4 to enter the UEFI BIOS, but we could not make it because of the IPMI KVM we used to manage the server.